III. Feature Description

A. Trunnion-Mounted Ball Design

• Pressure Load Distribution: The ball is supported by upper and lower trunnions, transferring media pressure loads to the valve body (not the seats). This eliminates seat overpressure, reducing wear and extending seal life—critical for 2500LB high-pressure service where floating balls would deform seats.
• Low Operational Torque: By isolating the ball from direct pressure loads, the trunnion design reduces torque by 30–50% compared to floating ball valves of the same size. A DN300 600LB trunnion valve requires only 300N·m of torque, vs. 500N·m for a floating equivalent—enabling manual operation for larger valves.
• Stable Sealing: Fixed ball alignment ensures uniform contact between the ball and seats, preventing uneven wear and maintaining consistent sealing performance over 100,000+ cycles. In oil & gas transmission lines, this design maintained Class VI sealing for 8+ years, vs. 3–4 years for floating valves.

B. Three-Piece (3PC) Body Structure

• On-Line Maintenance: The three-piece construction (body, bonnet, end flanges) allows internal components (ball, seats, stem) to be inspected, repaired, or replaced without removing the valve from the pipeline. This reduces downtime by 60–70% compared to one-piece or two-piece valves—critical for continuous-process facilities.
• Modular Versatility: End flanges can be configured with different connection types (RF/RTJ/BW) on the same valve, accommodating non-standard pipeline setups and reducing the need for adapters.
• Enhanced Structural Integrity: Forged 3PC components eliminate internal voids, ensuring resistance to cyclic pressure loads and thermal expansion. In petrochemical plants, this design withstood 50+ pressure surges (up to 120% of rated pressure) without deformation.

C. Full-Port Flow Design

• Minimized Pressure Drop: Reduces pumping energy costs by 15–20% in continuous-flow systems (e.g., cross-country oil pipelines). For a DN500 1500LB valve handling 5000m³/h of crude oil, this translates to ~$30k/year in energy savings.
• Unobstructed Media Passage: Prevents clogging by particulate media (e.g., sand, drilling mud) in upstream oil & gas applications. In offshore drilling rigs, full-port valves reduced pipeline blockages by 80% compared to reduced-port alternatives.
• Efficient Pigging: Compatible with pipeline pigging (cleaning/inspection tools), as the full bore allows pigs to pass through without obstruction—eliminating the need for bypass valves.

D. Forged Construction & Premium Materials

• Defect-Free Structure: Forging compacts the metal grain, eliminating porosity, shrinkage, and cracks common in cast valves. Ultrasonic testing (UT) confirms no internal defects, ensuring structural integrity under extreme pressure.
• Corrosion Resistance: Forged A105 carbon steel resists general corrosion in oil & gas media, while F316 stainless steel (with 2–3% molybdenum) enhances resistance to pitting and crevice corrosion in chloride-rich environments (e.g., seawater, chemical solvents).
• Wear-Resistant Sealing: PTFE seats with metal reinforcement resist galling (metal-to-metal adhesion) and chemical attack, while ENP-coated balls extend service life in abrasive media—outperforming uncoated balls by 3× in slurry applications.

E. Integrated Safety & Compliance Features

• Anti-Static Protection: Static electricity (generated by media flow and ball rotation) is discharged via a stainless steel spring—eliminating the risk of sparking in flammable media (e.g., natural gas, gasoline).
• Fire-Safe Performance: API 607 compliance ensures the valve maintains sealing integrity for 30 minutes at 750–1000℃. Graphite backup seals expand to fill gaps left by melted PTFE, preventing media leakage and containing fires.
• Double Block & Bleed (DBB): Two independent seats isolate the cavity, allowing trapped media to be vented or drained—enabling safe maintenance without shutting down the entire pipeline.

IV. Manufacturing Process & Quality Control

A. Raw Material Procurement & Inspection

• Material Verification: Forged A105 and F316 blanks undergo spectral analysis (XRF) to confirm chemical composition compliance with ASTM standards. Tensile, yield, and impact tests verify mechanical properties (e.g., A105 tensile strength ≥485MPa).
• Non-Destructive Testing (NDT): Forged components undergo ultrasonic testing (UT) to detect internal defects and magnetic particle testing (MPI) to inspect surface cracks. Only defect-free materials proceed to machining.
• Sealing Material Validation: PTFE resin is tested for purity (≥99.5% PTFE) and compliance with FDA 21 CFR 177.1550. Graphite packing and gaskets are verified for high-temperature stability (up to 538℃).

B. Forging Process

• Billet Heating: Metal billets are heated in a natural gas-fired furnace to 1100–1250℃—a temperature range that maximizes plasticity while avoiding grain growth.
• Precision Forging: Heated billets are forged into body, bonnet, and ball shapes using custom dies. The forging ratio is maintained at ≥3:1 to ensure dense grain structure and uniform mechanical properties.
• Heat Treatment: Forged components undergo annealing (A105: 900–950℃, air-cooled) to relieve forging stresses and improve ductility. F316 stainless steel components undergo solution annealing (1040–1150℃, water-cooled) to restore corrosion resistance.
• Descaling & Cleaning: Forged parts are shot-blasted to remove surface scale, then cleaned with ultrasonic baths to eliminate residual contaminants.

C. Precision Machining

• Body & Bonnet Machining: Flange faces are machined to flatness ≤0.02mm/m and surface roughness Ra 1.6μm. Seat pockets are honed to coaxiality ≤0.01mm relative to the bore, ensuring uniform ball-seat contact.
• Ball Machining: Forged balls are precision-ground to spherical accuracy ≤0.005mm and lapped to Ra ≤0.4μm. Full-port bores are machined to match pipeline dimensions, with no sharp edges to minimize flow turbulence.
• Stem Machining: Stems are turned and ground to precise diameter (±0.01mm) and polished to Ra ≤0.4μm. Threads (where applicable) are cut to ANSI/ASME B1.1 standards for secure actuator mounting.
• Dimensional Inspection: All components are inspected with coordinate measuring machines (CMMs) to verify compliance with design specifications. Inspection reports are retained for full traceability.

D. Surface Treatment & Coating

• Passivation: F316 stainless steel components undergo nitric acid passivation to form a protective chromium oxide layer—improving resistance to pitting and crevice corrosion.
• Epoxy Coating: A105 carbon steel components receive a two-layer epoxy coating (thickness ≥100μm) to protect against atmospheric corrosion. The coating meets ISO 12944-6 C5-M standards for high-corrosion environments.
• ENP Coating (Optional): Ball surfaces are coated with electroless nickel (thickness 50–100μm) for extreme wear resistance in abrasive media. The coating has a Rockwell hardness of ≥55 HRC.

E. Assembly & Comprehensive Testing

1. Component Cleaning: All parts are degreased and ultrasonic-cleaned to remove oil, debris, and metal particles—preventing contamination of sealing surfaces.
2. Assembly Sequence: Trunnion bearings are installed first, followed by the ball, stem, seats (with preloaded springs), packing, and bonnet. Fasteners are tightened in a crisscross pattern to uniform torque (per ASME B18.2.1).
3. Hydrostatic Testing:
   • Shell Test: 1.5× rated pressure is applied to the valve body for 30 minutes—no leakage, deformation, or lining delamination is permitted.
   • Seat Test: 1.1× rated pressure is applied to each seat (bidirectional) for 15 minutes. Leakage is measured via bubble counting, with Class VI compliance requiring ≤1 bubble/minute for DN50.
4. Operational Testing: The valve is cycled 50 times (open-close) to verify smooth operation and torque consistency. Manual worm gear operators are tested for ease of use and position indication accuracy.
5. Specialized Testing:
   • Fire-Safe Testing: Random samples undergo API 607 fire testing, with post-fire sealing performance verified via hydrostatic testing.
   • Fugitive Emissions Testing: ISO 15848-1 Class AH compliance is confirmed using methane and a flame ionization detector (FID).
   • Anti-Static Testing: Resistance is measured to ensure ≤10Ω, confirming effective static discharge.

F. Final Inspection & Documentation

• Visual Inspection: Checks for surface defects, coating integrity, and proper marking (size, pressure rating, serial number).
• Documentation Package: Each valve is shipped with Material Test Reports (MTRs), Hydrostatic Test Certificates, EN10204 3.1/3.2 Certificates, and Compliance Certificates (API, ASME, CE).
• Packaging: Valves are packaged in plywood crates with foam insulation to prevent damage during transportation. Flange ends are capped with plastic protectors, and operators are covered with waterproof bags.